Using the auditory brainstem response elicited by within-channel gaps to measure temporal resolution

The Auditory Brainstem Response (ABR) can be used to measure the early temporal activity of the auditory system. A gapin- noise ABR has been developed to measure the electrophysiological response to auditory stimulation without attending to the task. In the present study, young adults passively listened to stimuli of various gap widths in separate sequences. In a single sequence, two identical 15 ms filtered noise bursts, with a center frequency of either 750 or 3750 Hz, were presented separated by a gap (2, 5, 10, 20, 30, 40 or 50 ms in duration), with the second noise burst followed by an interstimulus interval of no less than 50 ms. An ABR was recorded at the onset of the first noise burst, before the gap (pre-gap), and at onset of the second noise burst, after the gap (post-gap). The gap duration had a suppressive effect on the amplitude of wave V for the noise burst following the gap. In contrast, wave V amplitude before the gap (i.e. the control) remained relatively constant. A significant difference was found between the amplitude of wave V elicited before and after the gap for gap durations equal to and below 20 and 5 ms, for 750 and 3750 Hz, respectively. The gap-in-noise ABR can potentially provide frequency-specific information for the study of temporal resolution in populations with a variety of hearing disorders.